Back plate of an electronic device



FIG. 1 is a front perspective view of a back plate of an electronic device showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines in the drawings illustrate portions of the back plate of an electronic device which form no part of the claimed design. 

CLAIM The ornamental design for a back plate of an electronic device, as shown and described. 